1. Field of the Invention
The invention generally relates to methods of inducing rain over arid or drought-ridden areas and, more specifically, to rain induced by supercontinuum laser beams.
2. Description of the Prior Art
Currently, rain induction methods involves seeding chemicals such a silver nitrate ions1 which could produce negative impact on the environment. With the advent of commercially available ultra high power compact ultrafast laser technology new methods to induce rain by high intensity light beams are proposed. These early laser studies have mostly been focused on laser pulses at 800 nm to activate nucleation and growth in laboratory chambers and only limited research in the free atmosphere. Seven years ago Rohwetter et. al.2 used Teramobile laser to research laser-induced water condensation in diffusion chamber and performed limited work in free atmosphere. They used backscattered light to evaluate efficiency of air filamentation as a cause of water condensation. However, they did not determine amount of rain from different states in the atmosphere. No marker for onset of rain was used.
Another approach that has been proposed is to use ultrashort UV laser pulses which are expected to offer a much more efficient activation of nucleation and growth in the atmosphere since it requires less photons than the NIR region3; however, UV light propagation in the atmosphere is much worse than NIR and it may be harmful for humans.